The present invention is related to automatic fastener driving equipment and more particularly to fastener holding assemblies for such equipment.
It has become a problem in industrial assembly operations to successfully utilize automatic fastener driving equipment without eventually damaging the workpiece due to misalignment of a fastener and misguided force against the automatic driving tool. More specifically, much difficulty has been experienced in the wood fastening field wherein automatic driving tools are utilized to secure wood workpieces together with screws. Ordinarily, screws are fed to an automatic fastener driving tool that is hand held and positioned by an operator. In operation, the screws are fed individually to the automatic driving tool and temporarily held by an expansible pair of jaws to project forwardly from the tool head. Unless the screw is held perpendicular to the workpiece and direct axial force is applied to the tool when starting the screw into the workpiece, the jaws will open and allow the screw to become disengaged from the driving tool, scratch across the surface of the workpiece, and fall to the floor. When this happens, the user seldom has sufficient time to retract the driving tool before it strikes the workpiece and inflicts further damage.
It has therefore been found to be desirable to design a clamp mechanism whereby each automatically fed fastener, such as a screw, may be held securely within the tool along a prescribed axis until it becomes firmly attached to the workpiece. With such a device, inadvertent disengagement of a fastener from the driving tool would be prevented, even though a misaligned force be applied between the driving tool and workpiece.